Adhesives are widely used in construction applications. For example, in the fabrication of wall systems (i.e., wallboard and wall frame assemblies), the industry typically constructs the wall frame on a horizontal work table and applies an adhesive to framing members of the wall frame. The adhesive is applied around the perimeter and in the "field" of the wall assembly. The field of the wallboard is the area within the perimeter of the wallboard. After application of the adhesive, 4 foot by 8 foot sections of wallboard (e.g., gypsum board) are placed onto the adhesive-coated framing members. The wall section is then raised to a vertical position for storage or use in constructing a house.
Fasteners (i.e., staples, screws, or nails) often are placed around the perimeter and in the field of the wallboard to provide additional strength to the assembly. By using fasteners, the wallboard and wall frame assembly can be raised almost immediately after the board is placed onto the adhesive on the framing member. The fasteners in the field in particular help avoid "wall pops." Wall pops occur because the wallboard and wall frame assembly may flex and distort when raised to a vertical position. Wall pops can cause the wallboard and wall frame assemblies to become loose and vibrate or rattle. If the wall pops are severe, wall repairs can be required.
The presence of fasteners in the field of the wallboard can cause various aesthetic problems. For example, the fastener has to be covered up by hand-applied overcoating, which requires additional manufacturing time and compromises the appearance of the finished wallboard and wall frame assembly.
The suitability of an adhesive for particular uses can be determined from the open time and green strength of the adhesive. "Open time" is the length of time that the adhesive is wet to the touch after applying the adhesive to a support. "Green strength" refers the load that the adhesive can bear at a particular time after application of the adhesive to a surface.